1. Field of the Invention
This invention relates to a slide fastener, and more particularly to a slide fastener which prevents jamming of foreign matter into the slider of the slide fastener.
2. Brief Description of the Prior Art
A slide fastener, commonly called a zipper or chuck, is generally provided with two fastener elements and a plurality of teeth arranged in row along each inner edge of a slender tape. The fastener elements are brought together to interlock together and separate apart by the movement of the slider in one direction or the other. The slide fastener is widely used, for example, in clothing, bags, sporting goods, household necessities and so forth.
Conventional types of slide fasteners, however, have serious defects. Foreign matter such as cloth, waste thread and the like, often become jammed in the clearance provided between the element-receiving openings of the slider and fastener elements. As a result, the slider will not slide properly or may not even slide at all if foreign matter becomes jammed between the teeth of the fastener elements and then the teeth engaged with each other. As a result, not only is the slider often damaged, but also clothing, bags and the like, which utilize slide fasteners, cannot be used any more. Moreover, the jammed foreign matter, which can even be part of the clothing or bag itself, or the contents of the bag may be damaged if caught in the slider. Various types of sliders have been utilized in an attempt to prevent foreign matter from entering and thereby jamming the slider. One such type of known slider is disclosed in applicant's own U.S. Pat. No. 4,121,326 wherein the two channel openings at the diverging end of a slider are provided with inturned lips thereby reducing the clearance between the fastener elements and the slider. The lips are made from wear-resistant material and ride against the sides of the fastener elements in an attempt to prevent foreign matter from entering into the two channels.
In another type of known slider, a plow or guard is disposed forwardly of the diverging end of the slider to prevent foreign material from reaching the slider and/or pushing under and over garments downwardly and upwardly, respectively, away from the channel entrances. One type of plow utilizes a cross bar which is disposed forwardly of the diverging end of the slider to extend perpendicularly to the line of travel of the slider in an attempt to prevent materials from reaching the slider. Examples of such sliders are disclosed in DeVore U.S. Pat. No. 2,072,220 and Samstegman U.S. Pat. No. 2,325,709.
In another type of known slider, the plow is generally in the form of a finger which extends forwardly to lie between the two tapes of a slide fastener. Examples of such sliders are disclosed by Foltis U.S. Pat. No. 2,840,877 and Jones U.S. Pat. No. 2,855,652.
In a further known type of slide fastener, the plow is generally in a V-shape having side edges which extend rearwardly and oppositely laterally outwardly from a central leading point. An example of this type of slider utilizing this particular plow construction is disclosed by Engel U.S. Pat. No. 2,456,822.
In another attempt to prevent foreign material from jamming a slide fastener, the forward edge portion of the upper and lower plates, which form the channel entrances at the diverging end of the slider, have been deformed upwardly and downwardly, respectively, to form a forwardly open projection that extends a short distance generally longitudinally of the corresponding slider channel. The upper and lower slider plates also include an inwardly directed rib which extends perpendicularly to the length of each entrance channel at the base of each projection. As the diverging end of the slider is pushed forwardly to close the fastener elements, cloth or other material which may be in the path of the slider are allowed to fill the projection until such cloth bunches up against the transverse rib thereby causing the slider to come to an abrupt stop theoretically before the jammed material is damaged by ripping or tearing. An example of a slider utilizing this particular construction is disclosed by Foltis U.S. Pat. No. 2,824,352.
In another known type of slider, longitudinal grooves are formed in the inturned side flanges which extend downwardly from the upper plate and upwardly from the lower plate at the diverging end portion of the slider. The grooves are disposed generally longitudinally of the line of travel of the slider so that foreign material which enters into the channels at the diverging end of the slider will enter the longitudinal grooves and follow the path of the grooves to thereby be conveyed rearwardly out of the slider. An example of this type of slider is disclosed by Mikulas U.S. Pat. No. 2,810,174.